The present invention relates to a lateral sliding sash (here the term "sash" is intended to encompass window and door to which this invention is applicable), and more particularly to a lateral sliding sash which allows the adjacent left and right sash pieces in the sash stile to be in alignment with each other when the sash is closed. Thus, the depth of the sash stile can be substantially the same as that of the sash piece, i.e. half that of the sash stile used in the conventional lateral sliding sash. Also, the sash pieces cover the lower sash stile to prevent any obstruction and dust from accumulating on the lower sash stile.
In the conventional lateral sliding sash, the sash pieces are mounted in the separated rails on the sash stile. Dust easily accumulates on the surface of the sash stile of the conventional lateral sliding sash. If dust and grime are allowed to accumulate on the rails then the opening or closing the sash will simply clamp the grime or obstructions between the lower sash stile and the bottom surface of the sash piece. Consequently, the movement of the sash piece is hindered, and the surface of the lower sash stile is damaged. In addition, when the rollers of the sash pieces pass over the obstruction, they are susceptible to damage and possible malfunction because of the conditions.
In particular, the lower sash stile of an aluminum window located near the sea will accumulate sand containing sea salt. This sand is difficult to remove. The damaged surface of the lower sash stile, mentioned above, will disrupt of the anodic oxidation film on the surface of the aluminum window, so that the aluminum substance is exposed. The salt ion will thus generate a chemical reaction with the aluminum ion. The resulting corrosion of the aluminum greatly reduces the durability of the aluminum window. Moreover, in snowy climates piled snow on the outer rail of the window will also hinder the movement of the sash pieces.
In order to prevent environmental noise and save energy, a variety of double-layered sashes are suggested to provide sound and thermal insulation. FIGS. 16 and 17 show two types of such double-layered sashes.
FIG. 16 shows a double-layered sash assembled with two single-layered two-piece lateral sliding windows parallel to one another. FIG. 17 shows a window assembled with inner and outer double-layered sashes in the same manner as the general single-layered window. The above windows still cannot avoid the problem of exposing the lower sash stile to the elements. Furthermore, the depth of the sash stile of such a window is equal to, or larger than, that of the wall, and therefore it is bulky when mounted in the wall. For solving this problem, the depth of the inner sash edge A is always increased a depth of d3, and the inner window surface is moved outwards from the inner wall surface B in order to moderate the oppressive feeling caused by lack of space. In many cases there is not sufficient space for the depth d3, thus the oppressive feeling cannot be avoided.
For thermal and sound insulation, the single-layered sash existing in the buiding is supposed to add a single-layered lateral sliding sash on the inner window edge C as shown in FIG. 18 to form a similar structure to that of FIG. 16. However, in this situation because the space for mounting inside the original sash is always insufficient, another window edge C' must be added. The addition will project inwards from the wall surface and is not only bad-looking but also requires further additional construction.
In the conventional sash, see FIG. 17, both the left and right sash pieces are double-layered. The thickness of the air enclosed between the inner and outer glass layers of each sash piece is less than that of the sash shown in FIG. 16. Thus insulation against sound and temperature is minimal. That is to say, if the sealing structure around the sash pieces are the same, the sound and thermal insulation effect is in proportion to the thickness of the air layer between the inner and outer glass layers. This has been proven through experiment.
Although the air layer of thickness d2, shown in FIG. 17, increases the sound and thermal insulation effect, the entire depth of the sash is greatly increased resulting in an extremely awkward and disadvantageous mounting of the sash as described above. The thickness d2 of the air layer of the two-layered sash piece cannot be increased further, and thus its effectiveness is extremely limited.
Since double-layered sash piece is thicker than single-layered sash piece, the fluctuation d4 from the left sash piece to the right sash piece is greater. The sash of FIG. 17 will cause excessive shadows which affect its ornamental effect. To solve this problem, it has been suggested that a plurality of fixed, unmovable single-piece sashes be mounted on the same plane and several pivoted windows be arranged at specified places for ventilation. However, with this kind of pivoted window, it is difficult to construct a large saash piece, and when it is opened, the space in the room is adversely affected. Such design is inconvenient when taking the effective use of space into consideration.